1. Field of the Invention
The present invention relates to an image forming apparatus for forming a sample image on a recording medium, detecting a state of the sample image, and controlling an image forming condition on the basis of the detection result.
2. Related Background Art
A conventional method such as image stabilization control is known. In this method, a sample image having predetermined gray-scale levels is formed on a recording medium, the image density of the sample image is measured, and an image forming condition or an image processing condition is changed on the basis of the measurement result, thereby obtaining an image having good gray-scale characteristics (e.g., U.S. Pat. No. 4,888,636, U.S. patent application Ser. No. 760,575). In an image stabilization control method, even when the characteristics of a photosensitive body have deteriorated or even when toner replenishment cannot be precisely performed, an image having gray-scale characteristics that are as high as possible can be obtained without maintenance by a service person.
However, even when the characteristics of the photosensitive body have deteriorated, such deterioration cannot be found early, or a necessary time for scheduling maintenance cannot be easily determined.
When a formed image has poor quality, it cannot be easily determined whether image quality is poor, even if the above-mentioned image stabilization control is sufficiently performed, or image quality is poor since the above-mentioned image stabilization control is not sufficiently performed.